2. amps-preamps
  3. 1290296447

12ax7 12AU7 EL34 / KT 88/ 6550 upgrades for PL2

I acquired a used primaluna prologue two a month or so ago. This is my first experience with tube amp. Coming from rotel amplification I am just wowed with the tubes. The PL2 had upgraded tung sol 6550s. Nice sound. But I changed to new issue Electro Harmonix H EL34EH. Ran-in the tubes two days straight with music. Was simply blown away with soundstage and tone! Guitar riffs and blues sound gorgeous! Bass isn't too shabby either. Quite enjoyable.

Then found a little more improvement by switching 12ax7s from stock to Electro Harmonix ($10 bucks each).

The tried changing out 12AU7 with some old used tunsol 5963/12au7 (made in the USA) and was not happy. Changed back to stock.

Does anybody have any good experiences with upgrading the 12ax7/12au7 and power tubes on the PL2. I would appreciate the advise. Tube rolling is so much fun!

My speakers are quad 22L2, cd player oppo bdp 83se and analog source is MMF5 w/ MMshure ML140E.
rohitdev

Showing 1 response by evilfij

evilfij
12 posts
 
I don't have the same amp, but the gold lion KT88s sounded the same if not better than either the original RCA 6550 or Genelex GEC KT88 or original Sylvania 6550 I have tried. The gold lions are expensive ($200 a quad) and I run my amps 6-8 hours a day so I am going to try the tungsol reissues next ($110 a quad).

I also found that the original telefunken 12ax7s in my preamps sound extremely good.

The bottom line is I would go with original small tubes and reissue kt88/6550 based on my experience.
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